Tuesday, July 27, 2010

What exactly is the 'plausible midfuture,' a term I have used here from early days without ever quite defining it?

It lies beyond the near future of technologies already on the drawing board, though some of today's tech may remain in use, just as some DC-3s are still flying. I think of the midfuture as beginning perhaps around midcentury, give or take a couple of decades. The world should still be largely familiar. Streetscapes of today do not differ obviously from those of the 1970s (at least in the US; China is a different matter). Car styles and clothing styles have changed, but the first 'new' thing a time traveller might notice are those people using cellphones and talking about stuff they found on the Internet.

The far end of the midfuture, when it shades into the far future, is naturally hazier, perhaps 200 years, give or take a couple of generations. A few DC-3s may still be flying, but by then only as exercises in historic preservation, and with multiple rebuildings like the Ship of Theseus. Travellers from 2010 would at once sense that they were in a different era. But much should still be recognizable, as our military institutions and uniforms have continuity with those of 1810 (but only in traces with those of 1610).

If there is anything like a Singularity, of course, all bets are off, which brings us to the 'plausible' half of my formulation. Prediction is difficult, said Yogi Berra, especially about the future. In the popular culture the future is passé; thus Disney relaunched Tomorrowland as a retro-future.

What rates as Plausible [TM] space tech, so far as human travel and habitation are concerned, has not changed much in the half century of space travel. The tech revolution of the recent and current era, cybernetics, has profoundly transformed robotic space travel - no one in the 1950s expected robotic Mars rovers, or Titan landings controlled from Pasadena. The anticipated hardware has not much changed (apart from the rather iffy prospects of elevators) just as cars and jetliners have changed less than anyone in the 50s expected.

And beyond the midfuture? Will technical progress, taken in all, continue at more or less the rate of the last 200 years? Or will it settle down into maturity and gradual refinement, as guns and sailing ships did from the 16th century until the 19th? But the far future is a long time. A few posts back I considered the era of 40,000 years from now, still a dip of the toe in the sea of far futurity.

What we want in our hearts - at least for purposes of Romance - is space opera: FTL starships, worlds by the dozen, the Galactic Empire or at least the Terran Empire. None of this is very plausible, which is a long ways from saying impossible. General Relativity is far above my math and physics pay grade. But to judge from discussion here, including commenters for whom it is not above their pay grade, GR does not actually rule out FTL. It merely imposes constraints, which can be largely tucked into the deep background mechanics, invisible to the story.

An alternative option is simply not to worry about Albert Einstein (an early scholar who followed Newton in refining Aristotle's speculations). Most fantasy writers do not belabor the pseudo-physics of dragons or magic, and are no worse off for it, and space opera is fundamentally 'science fantasy,' whether or not anyone uses a vorpal sword. The geek police never arrested Asimov or Bujold, and they have no greater authority over you.

That said, if you are regular reader of this blog you probably like and appreciate the trappings of hard SF, the crisp glitter of a Realistic [TM] spaceship against the velvet vastness of space. This too is justified. Again our sister genre, fantasy, points the way. Even though a fantasy world has magic, we still expect its swords to be sharp and its sailing ships to have a practical, seamanlike rig. (Not in all fantasy worlds, especially the dreamlike ones, but more often than not.)

So the leap into space opera does not compel us to abandon every standard and uncritically embrace our inner Hollywood. We are free to embrace it critically. What remains is the obligation to be consistent with our vision. (If you want real, Heinleinian torch drives, don't rate them in gigawatts.) Or, if you want the equivalent of gas turbine ships fighting with smoothbore cannon, gin up a background history that justifies it. The Old Race invented the drive, but they were peaceful, which is why they got wiped out, yada yada.

For that matter, truth to be told, if the story is good enough no one will really care.

47 comments:

Citizen Joe
said...

I guess I should open this up with the difference between FTL travel and FTL motion. When we want to get from star A to star B in a reasonable amount of time, we'll need net effective FTL travel. That being said, you don't actually have to MOVE FTL to do that. If you remove all the space between the two stars, you can leisurely step over the remaining space at a snail's pace. Typically, you see this as a wormhole. The Alcubierre (sp?) warp drive does a similar thing on a smaller scale. In any case, all of the relativity issues apply to moving close to light speed (or beyond) and those get sidestepped by never actually going that fast. Part of that theory is already observed. Space is currently larger than it is old, and it is expanding at a super luminal rate (I think). That means space can be made to expand, the only question is whether it can contract. Given the theory that gravity is a distortion in space-time, then we know space itself can be manipulated.

There is also a strong analogy between how electricity behaves and how gravity behaves. That leads to the question about induced currents having a gravity based analog. If the reason that gravity is a weak force stems from the theory that what we're sensing is the induced effect, then that leaving a higher power source of gravity someplace beyond our perception. Given the theories on dark matter and dark energy, those could be the sources of the induced gravity which we feel. Once the key to that mystery is unlocked, a whole flood of new possibilities will pour in.

For a very space-opera feel, the Royal Astronomer has suggested that future crewed space exploration may be carried out by adventurers. From a technical point of view it makes more sense to send robots, but the same could be said about landing drones atop Mount Everest. You get more data with a remote vehicle or robot, but less bragging rights.

Why did Sir Robert Mbotu, hereditary Chief Financial Officer of the Leased Estate of Zimbaze, go to Mars? Because it was there, my good man.

I've cooking up a mid-future setting for awhile now, with the human vs robots issue settled by non-invasic BCI's linking machinery to human minds via a light helmet- the brain managing to xcontrol machinbery and robots far more effectively thatn computers. A resuklt of this would be to have robots on the surface, humans in orbit controlling them, and some humans accompnying them (scouting out a base camp for the next wave of explorers)but allowing the robots to do much of the work.

One key factor of human explorers is that they can tell inastantly, without light speed lag or limited data from the camera feed, what the environent looks like. Remember that all things humans do, as ultimatelyfor humans. Having a robot check the acidity of the soil is fine, but a human will one day have to go there and state that the plateau would make for a great settlement, even if it is just to affirm what the robot said.

My mid-future could be extended even further into the far future, with wormholes liking the processers in a computer together to allow for near instantaneous processing, making robots more useful again. Then the cycle comes full circle again when someone maps out the human brain nueral pathway by neural pathay, and eventually manages to put small wormholes in the HUMAN brain, making it able to compete with computer brains again. (The effects of developing FTL don't just have to apply to travel you know ;) )

Most far future settings seem to have to ignore fully formed world building attempts though, as politics and social attitudes have to be plucked out of the blue, unless you want to try and develop 3000 of history in detail until you reach your wanted time.

I think that many of us would agree that the best way to have the elements that they wish to include in their scifi/science fantasy setting, weather they are technology or location wise, that one of two or both solutions can be utilized:

2) Describe only what that troupe can and cannot do at best and give a semi-plausible justification for its employment in the face of otherwise stone-hard logic.

Granted, if one wishes to keep some semblance of Realism [TM] in the technical aspects of the setting (let alone the social-political or even the economical realism of the setting. That's a can of worms I wouldn't wish upon ANYONE), there are some taboos that shouldn't be touched else leave one vulnerable to the all too great temptation of breaking all the rules of science. As many of us know, a good list of these "Shalt not" are listed at Atomic Rockets with associated links for explanations to great to summarize as to WHY they won't work realistically.

But if there are some troupes that your setting and story simply can't live without for any reason, such as my own, then following one or both of the previously mentioned guidelines "should" be able to allow one to get away with it.

And while we're on the subject matter, Rick made an interesting case of some of the familiar architecture and/or technology we're used to may still exist in the Plausible [TM] Mid-Future and beyond in one form or another. It makes logical sense that the technology and buildings we use today and/or inherited would still be around along with Jetson Tech since future advancement would blur with previous innovations since Eras aren't so clean cut from one to the next as many of us would believe.

Few stories and media that I have read and watched fully incorporate this blending of the "archaic" and the advanced in the every day of the setting. True, there are the occasional landmarks and cultural icons, but never really a mixture of technology, architecture, and culture in what is considered the every day. Arguably, such a use would potentially give more life and evolution to the daily life of the setting then the most accurate of researches of the subject matter in hand.

A story about the crew of an old spaceship that has been upgraded to FTL and now travels between stars decades after it was retired from service transporting passengers and cargo around the moons of Jupiter, after decades of being used to take explorers and colonists from Earth to Mars. The crew now struggles to keep the ship running and make a profit by carrying passengers and rare items to far-away planets...intigrating an old, rebuilt first generation stardrive into an interplanetary vehicle a century older still is a challange, to say the least...and those shady passengers and "rare items" that arn't always strickly legal, just add to the crews' woes. They can't compete with the newer liners and freighters purpose built and faster than any hope the crew of our old ship could have. They exist on the fringe, resembling those mechanics and pilots in the South Sea Islands between the World Wars (at least, as far as the Romance images of that time and place would have us believe), and having just as many adventures; their attitudes towards the new tech would be a mixture of contempt and envy while their feelings toward their own old tech would be a mixture of pride and disgust...they can see the end of their way of life and they don't know whether to mourn the ending or joyfully embrace the new...and wind up doing both, to some degree or other.

In many ways, I think that there's too much FTL in most science fiction these days. It's easy for an author to build new planets, but it takes work to put together a working solar system. I'd be really surprised if we got FTL before we got large amounts of space travel (unless it's say, wormhole based FTL). That means that there should be at least some sort of colonies in the solar system, even if they don't last long.The advantage of FTL from the author's perspective is that it lets them make the universe work like it does on Earth, instead of worrying about orbital mechanics. Still, where's the fun in that?

All one has to do is terraform Mars and Venus, add 250+ nation states for each and voila! Over 600 Earth-like locations with different cultures and terrain, all populated by humanoid life forms for the crew to explore, with no violation of the laws of physics. Who needs FTL?

As concerns culture, sociology and economics, I merely would one day like to find a popular sci-fi novel that does not focus exclusively on technology or exploration- the fact that grand economic history is sometimes cycular could help somewhat. Ian M Banks, Peter F Hamilton, Alastair Reynolds and a slew of American sci-fi writers do focus mostly on technology (and war....sigh). Nothing wrong with that at all, but focusing on future politicians and bankers would make for a nice change one day.

The starship Asgard. He knew her history, Uncle Chet had served in her. A hundred years earlier she had been built out in space as a space-to-space rocket ship; she was then the Prince of Wales. Years passed, her tubes were ripped out and a mass-conversion torch was kindled in her; she became the Einstein. More years passed, for nearly twenty she swung empty around Luna, a lifeless, outmoded hulk. Now in place of the torch she had Horst-Conrad impellers that clutched at the fabric of space itself; thanks to them she was now able to touch Mother Terra. To commemorate her rebirth she had been dubbed Asgard, heavenly home of the gods.

Who needs terraforming? You can do stuff with the current solar system just fine. People write fiction on modern Earth, why can't it be done on future Earth as well?Plus, there's plenty of strange things in colonization. Cities in tunnels where jumping over traffic is done, cities under giant domes, etc.

I think someone wiser than me once said that the window of reasonable predictive fiction (sci-fi) was 500 years. Beyond that it might as well be magic. Some one from 1510 would find our technological and cultural world largely incomprehensible. Space flight would be "magic" to the 16th century man since for him Newton's laws lay many decades ahead. To the scifi literate of today a "utility fog" of nanobots is just becoming imaginable but 50 or 75 years ago this too might have been "conjuring out of thin air".

true, though it does seem to me that any well-educated Briton from around the 1680's, when steam engines in mine works were being talked about, might manage to understand the internal combustion engine from the modern day if it was explained in simple terms. Some demands of the Putney debates of the mid 1600's strongly resemble (but not completely) our political system today. Those founding fathers debating on what should replace the Articles of Confederation might be surprised to know that some of the political debates that took place then (the electoral votes being one) still take place today.

@ Byron

Of course, I was merely thinking about your average space opera setting that doesn't try too hard with alien settings. Your comment about "jumping over" trains brought the new casino royale film to mind- imagine free-"running" in zero-g!

Well, if you're looking for a non-space based future, you'll need to wreck orbital space of Earth. That means an explosion of space industry which results in a catastrophic failure of orbital debris. That would ground any further launches. Right now, there are already thousands of orbiting bits of debris being tracked. It wouldn't take that much more to make Earth orbit inhospitable. That could be a result of ASAT lasers developed to prevent the spy sats from looking down on various nations. Unfortunately, that results in a nasty mess from the wreckage. Eventually, all the satellites break down and the orbital 'reef' prevents launching replacements. Communications become limited to line of sight and fiber optic cables.

Citizen Joe said:"Eventually, all the satellites break down and the orbital 'reef' prevents launching replacements. Communications become limited to line of sight and fiber optic cables."Until their orbits decayed and they burnt up in the atmosphere...after a couple of centuries at most, more likely decades; then there would be more launches into orbit and hopefully a better strategy for dealing with debris.

The every day life of a colonist on Mars or Titan (for example) might be the basis of a good story, if that character were intersting in-and-of-himself; using this character to explore those colonies'social structure and political enviornment might be fun.

Recently, on mr. Charles Stross blog, there was a discussion about a very important aspect of space colonization: What's the minimu population size needed to maintain indipendentyl the current civilization level?

He points out that most of the current technology requires massive infrastructure, a very wide skillset pool, a lot of wich undocumented etc. etc., and that any hope of having a truly idipendent colony,if you're not going to invoke magitech or AIs, would require very wide populations...

Apart from everything else, the complexity problem I think should be taken into account when dealing with future scenarios: too often we fall for a simplified view of the world...

Rick's colonization essay on Atomic Rockets mentions the problems of lack of infrastructure and skilled workers on new colonies. For this reason, as Sabersonic has said, there probably will be a mix of old and new technology present in colonies, the former locally made and the latter imported. I suspect that a major influence will be the 'appropriate technology' approach currently advocated for the developing world, since it emphasises the use of locally available materials and low-powered solutions.

The 'reef' would be all the debris that is either too small to track or is so erratic that the launch windows become too small. I'm sure that near the end of the boom, people took short cuts and tried to get through the reef, but that ended up with catastrophic failure and exacerbated the problem by adding their own bits to the orbiting debris cloud. While a hundred years later, the cloud may have decayed enough for orbital launches again, people would have found other solutions to their problems and lack of interest would have killed any other hopes of space travel.

The point isn't that the orbiting stuff would get hit. It is more of a problem of getting through all the clutter without getting hit.

Advanced technology may resemble magic at first glance, but it is still just technology. An ancient might be astounded by the modern world, but I suspect that he would be quite comfortable after a few days of remedial education. Social customs and cultural mores would continue to be stumbling blocks, but the human condition simply hasn’t changed all that much.

For a far-future setting, I would gloss over technological details. There may be an instantaneous global communications network, but I wouldn’t bother to explain what the interface looks like or how exactly it works. The reader may assume a gadget with buttons and dials or an impulse-shielded skeletal antenna linked to cerebral microprocessor.

I've heard that for short term genetic diversity, you need 50 couples; for long term genetic diversity, you need 500 couples. For long term technological diversity, I'd think that you'd need three to five times that number; ten times (5000) would be better, especially if you didn't expect a very high rate of emigration.

5000 couples equals 10,000 people in total, which Rick gives as the absolute minimum for a viable technological colony in the essay I mentioned above, with 100,000 suggested as a better number, to ensure that the necessary number of specialists to maintain a technological civilization could be supported. A colony with a population much lower than 10,000 would either have to resign itself to a lower level of technology or would be an outpost relying on extensive imports from Earth.

One of the reasons for large numbers of people in order to maintain technological infrastructure was specialization, so many of the layers of infrastructure were not (strictly speaking) technological infrastructure at all. Under the tech staff, skilled mechanics and craftsmen/machinists etc. are layers of support workers to feed, house, transport, cloth and entertain everyone else.

I can envision a plausible midfuture where many layers of support have been rendered redundant. (In the current future this has been achieved by outsourcing). Devices like "3D printers" reduce the need for skilled craftsmen to build prototypes or machinists to build tools and dies, and similar technology exists for medicine and food as well. Why import chefs and cooking staff if you have a 3D food "printer" which can mix and process food items (a recent MIT Technology Review article highlighted several types of high tech food processors)? If people accept high levels of genetic modification, they might have a photosynthetic layer where we have skin and not need much in the way of agriculture at all.

Thinking farther into the future, skills could be downloaded from master craftsmen and either "embedded" into high tech devices or transferred to the person who needs these skills (admittedly Magitech, but who knows?). Even extending the idea of Google and ubiquitous communication devises leads to similar conclusions, with the added question of what happens to a society if the primary skill is referencing existing information rather than creating new things?

I have mentioned in earlier posts that the mid future will probably sneak up on us unannounced, as small changes like cell phones becoming cheap and universal spread through society (who would have predicted the growth of texting, "Sousvellance" [ubiquitous coverage by cellphone camera wielding citizens rather than "top down" surveillance by a central authority], flashmobs and so on) rather than some single "big idea".

@Cityside: That's a great article. To keep an old spaceship flying, you have to maintain parts and equipment that several generations old in terms of technology. Then there is the effects of just being space:

What does this mean for the effects of weathering on a ship in space? Manufacture will have the biggest effect on how long a ship will last and not on exposure to space. This means "mass produced" space craft would have problems of outgassing of volatile materials, housings sealing shut because the washers melted, etc.

However, LEO and exposure can degrade unprotected mirrors. Turns out that unprotected mirrors can have degraded behavior. It doesn't speak well for unprotected laser mirrors.

But, as I said in the beginning, the biggest impediment to running an old spaceship is the electronics and flight systems hardware. Try taking a Gemini capsule out of the Air and Space Museum and make it spaceworthy again. It will cost you about as much, if not more, to refurbish it as it did to build it, let alone get it back into space again.

So that 200 year old Firefly class freighter is a yard queen and will cost you more to keep running, than buying a new or relatively new ship.

Looking at the posts on hanger queens and "space reefs" brings a thought to mind (which is probably better suited to "The Aesthetics of Space Travel")

Spacecraft of any sort will need protection from space debris, the erosive effects of atomic oxygen and other assorted hazards, so a common design theme of near future spacecraft will be the erection of a protective canopy in the direction of travel. This could be a close in Whipple shield or a much larger wake shield (perhaps inflated and filled with a high density foam).

Ships designed for long duration flights will resemble sailing ships with the inflated wake shield filing the field of view. Ships designed for even longer term duration missions might also stack items around the central core, giving the ship the rough outline of a bundle of pipes or a golf tee (flared out in the direction of travel to provide maximum protection against debris and radiation).

This might not be possible for all types of ships or facilities (a wake shield to protect the solar panels and radiators of the ISS would be enormous), but given the potential of the problem, something along these lines might become standard practice (just as there are common engineering solutions to other problems, so bridges, ships, aircraft etc. look very similar despite the country of origin).

Welcome to another new commenter, and obviously a fan of Starman Jones, a book that hugely shaped my image of interstellar travel.

Special thanks to Winch for an entertaining surprise - going to Atomic Rockets and finding an essay I completely forgot writing (just past halfway down).

Note that my population estimates are for classical opera colonies on shirtsleeves planets - if you are dealing with spacehabs it is a different story. IMHO it is very demanding for a spacehab or group of habs to be fully independent economically of habitable planets.

Habitable planets, after all, are cheap to live on - that is more or less the meaning of 'habitable.'

For habs to make it on their own you'd probably need to assume a techlevel so high as to be 'post specialist,' as Thucydides suggests above. Which starts to get close to those classic far future civilizations where everyone is artistic because the tech runs itself.

But contrary to the idea that they'd be helplessly ignorant of their own tech, there could easily be geek and gearhead subcultures that play with the stuff not to 'preserve knowledge,' but because it is cool.

"I'd think that you'd need three to five times that number; ten times (5000)"

I think that's a major underestimate. That is the estimated population of the Tasmanian aborigines, & over the 10000 years of their isolation they gradually *lost* technologies, including such relatively simple ones like fishing, awls, needles. (I have this information from "Guns, Germs, & Steel" by Jared Diamond.)

To maintain an industrial level of technology, several million would be a more plausible minimum.

To me, there would be a number of differences between an extrasolar colony and an isolated island society like that of Tasmania that would allow the former to maintain their technology where the latter did not.Firstly, the colonists are deliberately setting out to found a new settlement on another world, while evidence suggests that the Tasmanians gradually migrated via a land bridge that was flooded at the end of the Last Ice Age.Secondly, the colonists, no matter how tough and self-reliant, are still products of Earth's postindustrial civilization, and would therefore understand the concepts of progress and of improving the lives of themselves and their descendants. The Tasmanians, on the other hand, were hunter-gatherers, content to live the same lifestyle for millennia.Finally, assuming FTL or high-speed STL travel, the colony will not be totally isolated from the rest of human society, and can therefore trade knowledge and materials with visiting ships. While trade did exist between Indonesia and Arnhem Land in the north of Australia for centuries, Tasmania appears to have remained virtually isolated from the flooding of the land bridge until the arrival of European explorers in the 17th century.For these reasons, it seems at least plausible that a colony with a population of ten thousand could maintain basic industrial technology, while the similarly sized Tasmanian population was unable to maintain its own.

"For these reasons, it seems at least plausible that a colony with a population of ten thousand could maintain basic industrial technology, while the similarly sized Tasmanian population was unable to maintain its own."

Actually it seems implausible that an extrasolar colony would not grow to much larger populations anyway. If there is a planet that is sufficiently earthlike that settlers can breath the air & grow crops in the open, it is hard to see how there could be insufficient living space to support many millions. If the extrasolar colonists are living in O'neill type habitats then a solar systems carrying capacity would be more in the range of trillions.

A population of thousands would exist for only a brief period soon after initial settlment.

The estimate of 10,000 was intended to be the population at the time of settlement, and would of course grow after that. My point was that a larger initial population was not necessarily needed to maintain a technological civilization.Rick's essay points out that given a population doubling time of a century, it would still take a colony of 100,000 (ten times the low-end estimate) roughly 700 years to grow to a population of 10 million.

Which would be rather long for a population in a new colony system with an enormous amount of space to expand into. That doubling time would be equivalent to between 2 & 3 children per couple. 4 to 5 per couple was fairly typical during the post WWII baby boom & would give a doubling time of 20 to 30 years.

IIRC 10 children wasn't uncommon in a geneology I saw for colonial era Massachusets, but something observed in a post-industrial revolution society would be more relevant to an off earth colony.

I'd agree with Jim about how fast humans can fill up a world. Doubling the population 3 to 5 times a century sounds about right for the first few centuries of a new colony, so even a fairly small initial population can expand to fill a world in a relitively short period of time.

I agree with the comment made by Jim Baerg regarding how fast Humans can breed, but a question that hasn't been raised, and quite surprisingly, is how a new colony could be augmented by robotics.

A fledging society with an infantile industrial base would certainly make use of automata powered by alternative renewable energy sources to handle the menial labour. It's possible that these machines would even proceed the presence of Humans at the colony world, construct the habitats, mining facilities, solar and wind farms etc...

This would reduce the pressures of the initial Human population of having to breed out a work force.

Rick's essay does talk about shorter doubling times, setting the limit at about once a generation, which assuming a generation is around 20 years gives five population doublings per century, or 10x overall increase per century.Of course, the essay also points out that even doubling every century means around half the women of childbearing age are having three or four children. Doubling every 20 years suggests that most women are having more than that, and are starting to have them at a young age. For example, the Amish of North America have roughly this doubling rate, and among them the average family size is 8-10 children, with people marrying in their late teens or early twenties. Such large families and early marriages might have implications for the status of women in the colonies: do they have the same opportunities for education and employment as men, or is their place in society more as mothers and housewives? It may turn out that traditionalist groups like the Amish are more successful as colonists, or that colonists from mainstream society will grow to be more like them.

Women spending more time pregnant would be hard on gender equality, but the longer life spans that can be expected in the future would tend to counteract that since the fraction of her lifespan spent pregnant or looking after very young children would still be much smaller than on pre-industrial earth.

Reproductive success seems more like a trope from a Heinlein novel rather than what we can expect in the 21rst century.

Ubiquitous communications and the Internet provide easy access to information and templates, steriolithography and 3D printing provide the ability to manufacture parts and even organs, while robotics provides the muscle.

Having lots of people is nice (increasing human interaction is probably the true cause of culture and innovation) but not a necessary precondition to having and maintaining an advanced technological civilization.

Still having and raising children is a primary biological drive, and unless we create post humans who are lacking these drives (and I suspect any post humans who are missing these drives will not be a successful species no matter how smart and aggressive they are), we will see the solar system and eventually the galaxy fill with our descendents.

It's possible that by the time 3d printers have become cheap and mature enough for colonies to rely on them for most of their manufacturing, the most advanced products may be beyond their capabilities, if they include smart materials with microscopic components that can only be made by nanofactories.Additionally, skilled programmers would probably be needed if new templates had to be added to the printer's memory, or if existing templates had to be modified beyond existing basic options such as colour, shape, etc. Unless the colony is a true post-scarcity society where the programmers can afford to program as a hobby, there will need to be a certain minimum population to support them and allow them to work full-time as specialists.

In my view, Realistic[TM] futures are the bleakest and most pessimistic ones. Remember Wall-E?Technology advances to the point where we don't need specialists, that is after we put farmers and manual workers out of work...cos robots do them better.

Simply, once a robot does something cheaper and faster than a person does it, that person gets sacked. Once the robot that keeps an eye on the first robot does its thing better than a person, person gets sacked. Unemployment FTW!!

A couple of notes on population growth. I used 30 years to a generation, figuring the childbearing years from roughly 20 to 40.

Doubling each generation, 10x per century, pretty well fits the historical case of Utah, which had relatively little in-migration from 1880 to 1980, and a Mormon culture that encouraged big families.

On the scale of society needed for an industrial civilization, this is hard to measure! One metric: Sweden, with 8 million people, builds its own fighter jets, or used to. France, with 65 million people, builds jets, subs, and ballistic missiles, but to really do a space program it had to bring in the rest of Europe.

Of course both those countries are embedded in a larger industrial civilization. Doing it in isolation would be cheaper in some ways (cheap oil!), but more expensive in many others.

So I'd say that with industrial processes broadly like our own, 10 million might well be the practical limit for maintaining an industrial civilization. Techs such as 3-D printers could push this number down, but by how many orders of magnitude?

The problem of the music industry is due to information on the net being unsecure...a result of the Internet expanding out of control I think.

For the moment, I'm trying to wrap my mind around something that people would live in interstellar colonies for. Industry? Cheap robotic factories in orbit. Mining? Two robots and a guy in Jovian orbit. Any more ideas?

Past comments on this blog have targeted environmental catastrophe as the impetus to space colonization: if humanity absolutely had to colonize space to ensure its survival say within the next 100 years: How would it proceed: Would governments work together in a world coalition? Would a few competing coalitions form? -Or would it be every country for themselves? What would be the best avenue for constructing an off-Earth colony in the short term that could survive in the long term: a colony on Mars, Venus, the Moon, the asteroids, one or two large space habitats, several small space habitats, all of the above? Who would be allowed to go up to salvation and who would be forced to stay behind. . . and would they stay behind willingly. Deciding what ratios of races, religious, nationalities, classes, etc. that would be spared via 'Noah's Arks' and what divisions of humanity would be left behind to face the Great Flood Part Deux and/or Snowball Earth might make for an interesting, if potentially terrifying story.